Answer
Kinetic energies of both Car A and Car B are same.
Work Step by Step
$v_{B}=2v_{A}$
$m_{A}=4m_{B}$
Kinetic energy of Car A =$\frac{1}{2}m_{A}v_{A}^{2}=\frac{1}{2}\times4m_{B}\times\frac{1}{4}v_{B}^{2}=\frac{1}{2}m_{B}v_{B}^{2}$=Kinetic energy of Car B
